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USB: serial: add support for multiple read urbs

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Add support for multiple read urbs to generic read implementation.

Use a static array of two read urbs for now which is enough to get a
50% throughput increase in one test setup.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Johan Hovold
2011-11-06 19:06:37 +01:00
committed by Greg Kroah-Hartman
parent f5230a53c1
commit d83b405383
3 changed files with 101 additions and 41 deletions
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83
drivers/usb/serial/generic.c
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@@ -1,7 +1,7 @@
/*
* USB Serial Converter Generic functions
*
* Copyright (C) 2010 Johan Hovold (jhovold@gmail.com)
* Copyright (C) 2010 - 2011 Johan Hovold (jhovold@gmail.com)
* Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
*
* This program is free software; you can redistribute it and/or
@@ -132,7 +132,7 @@ int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port
/* if we have a bulk endpoint, start reading from it */
if (port->bulk_in_size)
result = usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
return result;
}
@@ -157,8 +157,10 @@ static void generic_cleanup(struct usb_serial_port *port)
kfifo_reset_out(&port->write_fifo);
spin_unlock_irqrestore(&port->lock, flags);
}
if (port->bulk_in_size)
usb_kill_urb(port->read_urb);
if (port->bulk_in_size) {
for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
usb_kill_urb(port->read_urbs[i]);
}
}
}
@@ -308,19 +310,52 @@ int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
return chars;
}
int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
int index, gfp_t mem_flags)
{
int res;
if (!test_and_clear_bit(index, &port->read_urbs_free))
return 0;
dbg("%s - port %d, urb %d\n", __func__, port->number, index);
res = usb_submit_urb(port->read_urbs[index], mem_flags);
if (res) {
if (res != -EPERM) {
dev_err(&port->dev,
"%s - usb_submit_urb failed: %d\n",
__func__, res);
}
set_bit(index, &port->read_urbs_free);
return res;
}
return 0;
}
int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
gfp_t mem_flags)
{
int result;
int res;
int i;
result = usb_submit_urb(port->read_urb, mem_flags);
if (result && result != -EPERM) {
dev_err(&port->dev, "%s - error submitting urb: %d\n",
__func__, result);
dbg("%s - port %d", __func__, port->number);
for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
if (res)
goto err;
}
return result;
return 0;
err:
for (; i >= 0; --i)
usb_kill_urb(port->read_urbs[i]);
return res;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urb);
EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
void usb_serial_generic_process_read_urb(struct urb *urb)
{
@@ -356,14 +391,19 @@ void usb_serial_generic_read_bulk_callback(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
unsigned char *data = urb->transfer_buffer;
int status = urb->status;
unsigned long flags;
int i;
dbg("%s - port %d", __func__, port->number);
for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
if (urb == port->read_urbs[i])
break;
}
set_bit(i, &port->read_urbs_free);
if (unlikely(status != 0)) {
dbg("%s - nonzero read bulk status received: %d",
__func__, status);
dbg("%s - port %d, urb %d, len %d\n", __func__, port->number, i,
urb->actual_length);
if (urb->status) {
dbg("%s - non-zero urb status: %d\n", __func__, urb->status);
return;
}
@@ -376,7 +416,7 @@ void usb_serial_generic_read_bulk_callback(struct urb *urb)
port->throttled = port->throttle_req;
if (!port->throttled) {
spin_unlock_irqrestore(&port->lock, flags);
usb_serial_generic_submit_read_urb(port, GFP_ATOMIC);
usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
} else
spin_unlock_irqrestore(&port->lock, flags);
}
@@ -443,7 +483,7 @@ void usb_serial_generic_unthrottle(struct tty_struct *tty)
spin_unlock_irq(&port->lock);
if (was_throttled)
usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
@@ -509,8 +549,9 @@ int usb_serial_generic_resume(struct usb_serial *serial)
if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
continue;
if (port->read_urb) {
r = usb_submit_urb(port->read_urb, GFP_NOIO);
if (port->bulk_in_size) {
r = usb_serial_generic_submit_read_urbs(port,
GFP_NOIO);
if (r < 0)
c++;
}